The $\alpha +d\to {}^6\mathrm{Li}+\gamma$ radiative capture is studied in order to predict the ${}^6\mathrm{Li}$ primordial abundance. Within a two-body framework, the $\alpha$ particle and the deuteron are considered the structureless constituents of ${}^6\mathrm{Li}$. Five $\alpha +d$ potentials are used to solve the two-body problem: four of them are taken from the literature, only one having also a tensor component. A fifth model is here constructed in order to reproduce, besides the ${}^6\mathrm{Li}$ static properties as binding energy, magnetic dipole, and electric quadrupole moments, also the $S$-state asymptotic normalization coefficient (ANC). The two-body bound and scattering problem is solved with different techniques, in order to minimize the numerical uncertainty of the present results. The long-wavelength approximation is used, and therefore only the electric dipole and quadrupole operators are retained. The astrophysical $S$ factor is found to be significantly sensitive to the ANC, but in all the cases in good agreement with the available experimental data. The theoretical uncertainty has been estimated of the order of few percent when the potentials which reproduce the ANC are considered, but increases up to $\simeq 20\%$ when all five potential models are retained. The effect of this $S$-factor prediction on the ${}^6\mathrm{Li}$ primordial abundance is studied, using the public code PArthENoPE. For the five models considered here we find ${}^6\mathrm{Li}/\text{H}=(0.9–1.8)\times {10}^{-14}$, with the baryon density parameter in the 3-$\sigma$ range of Planck 2015 analysis, ${\mathrm{\Omega }}_b{h}^2=0.02226\pm 0.00023$.

Background: The angular distribution of fission fragments or products is a sensitive probe to investigate non-compound-nucleus (NCN) fission. However, the gross angular distribution cannot distinguish between different NCN fission processes. Both preequilibrium fission and quasifission contribute to NCN fission and would both result in deviations from the statistical saddle point model (SSPM). Mass-resolved angular distributions of the fission product offers the possibility to distinguish between the two mechanisms [Sodaye et al., Phys. Rev. C 95, 014612 (2017); Tripathi et al., Phys. Rev. C 88, 024603 (2013); Vorkapic and Ivanisevic, Phys. Rev. C 55, 2711 (1997)].

Purpose: Mass and mass-resolved angular distributions of fission products have been measured in the ${}^{16}\mathrm{O}+{}^{238}\mathrm{U}$ reaction at $E_{\mathrm{lab}}=85.3\mathrm{MeV}$ to investigate the dominant NCN fission mechanism at sub-barrier energy.

Method: Mass and mass-resolved angular distributions were measured by recoil catcher technique followed by offline γ-ray spectrometry.

Results: The mass distribution was observed to be predominantly asymmetric. The angular anisotropy of the fission products was observed to be independent of their mass.

Conclusions: The mass independence of the angular anisotropy suggested quasifission to be the dominant NCN fission process. This was further confirmed from the underestimation of angular anisotropy by theoretical calculations even after including the contribution from preequilibrium fission.

We show that in a central nucleus-nucleus collision, the variation of the mean transverse mass with the multiplicity is determined, up to a rescaling, by the variation of the energy over entropy ratio as a function of the entropy density, thus providing a direct link between experimental data and the equation of state. Each colliding energy thus probes the equation of state at an effective entropy density, whose approximate value is 19 ${\mathrm{fm}}^{-3}$ for Au+Au collisions at 200 GeV and 41 ${\mathrm{fm}}^{-3}$ for Pb+Pb collisions at 2.76 TeV, corresponding to temperatures of 227 and 279 MeV if the equation of state is taken from lattice calculations. The relative change of the mean transverse mass as a function of the colliding energy gives a direct measure of the pressure over energy density ratio $P/\epsilon$, at the corresponding effective density. Using Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) data, we obtain $P/\epsilon =0.21\pm 0.10$, in agreement with the lattice value $P/\epsilon =0.23$ in the corresponding temperature range. Measurements over a wide range of colliding energies using a single detector with good particle identification would help reduce the error.

Lifetimes of excited states in the neutron-deficient nucleus ${}^{61}\mathrm{Zn}$ were measured employing the recoil-distance Doppler-shift (RDDS) and the electronic fast-timing methods at the University of Cologne. The nucleus of interest was populated as an evaporation residue in ${}^{40}\mathrm{Ca}({}^{24}\mathrm{Mg},n2p){}^{61}\mathrm{Zn}$ and ${}^{58}\mathrm{Ni}(\alpha ,n){}^{61}\mathrm{Zn}$ reactions at 67 and 19 MeV, respectively. Five lifetimes were measured for the first time, including the lifetime of the $5/2_1^{-}$ isomer at 124 keV. Short lifetimes from the RDDS analysis are corrected for Doppler-shift attenuation (DSA) in the target and stopper foils. Ambiguous observations in previous measurements were resolved. The obtained lifetimes are compared to predictions from different sets of shell-model calculations in the $fp$, $f_{5/2}p{g}_{9/2}$, and multishell $fp\text{−}{g}_{9/2}{d}_{5/2}$ model spaces. The band built on the $9/2_1^{+}$ state exhibits a prolate deformation with $\beta \approx 0.24$. Especially, the inclusion of cross-shell excitation into the $1d_{5/2}$ orbital is found to be decisive for the description of collectivity in the first excited positive-parity band.

The thick target neutron yield from a ${}^{16}{\mathrm{O}}^{6+}$ beam on a thick ${}^{27}\mathrm{Al}$ target at 120- and 142-MeV (7.5- and 8.8-MeV/nucleon, respectively) incident energies is presented and compared with theoretical calculations. The theoretical estimates for the yield of a high-energy neutron was obtained using a preequilibrium (PEQ) heavy-ion reaction model (hion), whereas that for the low-energy part was obtained using the standard evaporation models pace4 and empire 3.2. In the present data a significant PEQ contribution, $\sim 2\%$ to 3% of the evaporation contribution, is observed even at projectile energies below 10 MeV/nucleon. The measured energy spectrum of neutrons for $E>20\mathrm{MeV}$ (the predominant PEQ region) is in good agreement with the PEQ model code hion.

In this work we study the implications of light quark pionic matter at finite temperatures on the properties of open and hidden charm mesons. Meson-meson interactions are described by means of a chiral unitary approach accounting for coupled-channel effects. The in-medium Lippmann-Schwinger equations, which consider the change in self-energy that the mesons acquire from interacting with the surrounding pionic matter, are solved self-consistently, and the spectral functions of the mesons in the hot pion bath are obtained. It is observed that the charmed mesons develop a quite substantial pion induced width, being several tens of MeV at a temperature of 150 MeV. The $J/\psi$ meson stays narrow, but its pionic width at 150 MeV, found to be around 0.1 MeV, is already larger than its vacuum width.

A generalization of the quantum van der Waals equation of state for a multicomponent system in the grand-canonical ensemble is proposed. The model includes quantum statistical effects and allows us to specify the parameters characterizing repulsive and attractive forces for each pair of particle species. The model is applied to the description of asymmetric nuclear matter and also for mixtures of interacting nucleons and nuclei. Applications of the model to the equation of state of an interacting hadron resonance gas are discussed.

It is crucial to measure reaction cross sections relevant to the astrophysical $\gamma$ process so that theoretical reaction rates can be tested and validated with experimental data. The total cross sections for the ${}^{162}\mathrm{Er}(p,\gamma ){}^{163}\mathrm{Tm}$ and the ${}^{162}\mathrm{Er}(p,n){}^{162}\mathrm{Tm}$ reactions have been measured by the activation method in center-of-mass energies from 3.973 to 8.944 MeV and from 5.962 to 8.944 MeV, respectively. The nucleus ${}^{162}\mathrm{Er}$ is the heaviest $p$ nuclide to be measured by the activation method using $\gamma$-ray spectroscopy, so far. It is important to note that the energy range for the $(p,\gamma )$ reaction measurement covers a large fraction of the astrophysically relevant energy region between 2.71 and 5.34 MeV. The targets were prepared by evaporating $28.2\%$ isotopically enriched ${}^{162}\mathrm{Er}_2{\mathrm{O}}_3$ powder onto carbon backing foils, and bombarded with proton beams provided by the FN Tandem Accelerator at the University of Notre Dame. The reaction yields have been determined by the observed activity of produced radioactive isotopes, which was detected offline by a high-purity germanium detector. The results are presented and compared with calculations from two statistical model codes: non-smoker and talys.

In this work we present a newly constructed equation of state (EoS), applicable to stellar core collapse and neutron star mergers including the entire baryon octet. Our EoS is compatible with the main constraints from nuclear physics and, in particular, with a maximum mass for cold $\beta$-equilibrated neutron stars of $2M_{\odot }$ in agreement with recent observations. As an application of our new EoS, we compute numerical stationary models for rapidly (rigidly) rotating hot neutron stars. We consider maximum masses of hot stars, such as protoneutron stars or hypermassive neutron stars in the postmerger phase of binary neutron star coalescence. The universality of $I\text{−}Q$ relations at nonzero temperature for fast rotating models, comparing a purely nuclear EoS with its counterparts containing $\mathrm{\Lambda }$ hyperons or the entire baryon octet, respectively, is discussed, too. We find that the $I\text{−}Q$ universality is broken in our models when thermal effects become important, independent on the presence of entropy gradients. Thus, the use of $I\text{−}Q$ relations for the analysis of protoneutron stars or merger remnant data, including gravitational wave signals from the last stages of binary neutron star mergers, should be regarded with care.

The production cross sections of several isotopes of Hs and their properties are considered. The optimal reactions are predicted for producing ${}^{268–271}\mathrm{Hs}$. The possible $\alpha$-decay chains including these isotopes are analyzed and compared with the available experimental data. The number of new isomeric states is predicted in the nuclei of these $\alpha$-decay chains. The role of $\alpha$ decay in the identification of these isomeric states is discussed.

Half-lives and energies of $\gamma$ rays emitted in the decay of isomeric states of nuclei in the vicinity of the doubly magic ${}^{100}\mathrm{Sn}$ were measured in a decay spectroscopy experiment at Rikagaku Kenkyusho (The Institute of Physical and Chemical Research) of Japan Nishina Center. The measured half-lives, some with improved precision, are consistent with literature values. Three new results include a 55-keV $E2\gamma$ ray from a new $\left(4^{+}\right)$ isomer with $T_{1/2}=0.23\left(6\right)\mu \mathrm{s}$ in ${}^{92}\mathrm{Rh}$, a 44-keV $E2\gamma$ ray from the $\left({15}^{+}\right)$ isomer in ${}^{96}\mathrm{Ag}$, and $T_{1/2}\left(6^{+}\right)=13\left(2\right)$ ns in ${}^{98}\mathrm{Cd}$. Shell-model calculations of electromagnetic transition strengths in the $(p_{1/2},g_{9/2})$ model space agree with the experimental results. In addition, experimental isomeric ratios were compared to the theoretical predictions derived with an abrasion-ablation model and the sharp cutoff model. The results agreed within a factor of 2 for most isomers. From the nonobservation of time-delayed $\gamma$ rays in ${}^{100}\mathrm{Sn}$, new constraints on the $T_{1/2}$, $\gamma$-ray energy, and internal conversion coefficients are proposed for the hypothetical isomer in ${}^{100}\mathrm{Sn}$.

We explore spin and pseudospin symmetries in the single-$\mathrm{\Lambda }$ spectrum within the framework of relativistic mean-field theory. We find that the spin symmetry of the single-$\mathrm{\Lambda }$ spectrum maintains, which is consistent with experimental results of small spin-orbit splitting, whereas the approximate pseudospin symmetry is quite similar to that of nucleons. More interestingly, the $\omega \mathrm{\Lambda }\mathrm{\Lambda }$ tensor coupling has opposite effects on these symmetries which makes the spin symmetry better but the pseudospin symmetry worse. This can be understood by the negative value of the $\omega \mathrm{\Lambda }\mathrm{\Lambda }$ tensor potential, which reduces the spin-orbit potential while increasing the pseudospin-orbit potential.

Pion production in nucleus-nucleus collisions at intermediate energies was modeled in the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model. The effects of nucleon-nucleon short-range correlations in initialization and mean-field potential, isospin-dependent in-medium baryon-baryon elastic and inelastic cross sections, and pion in-medium effect are all considered in this model. It is found that the ratio and yields of ${\pi }^{-}\mathrm{and}{\pi }^{+}$ in Au + Au reaction at 400 MeV/nucleon reproduce the FOPI data at GSI very well especially with a soft symmetry energy in the present transport model. Predictions on the single and double ${\pi }^{-}/{\pi }^{+}$ ratio are made for the isotope reaction systems ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ and ${}^{108}\mathrm{Sn}+{}^{112}\mathrm{Sn}$ at 300 MeV/nucleon since related experiments are being carried out at RIKEN in Japan.

There is a serious well-known problem of noticeable disagreements between the partial photoneutron cross sections obtained in various experiments. Such data were mainly determined using quasimonoenergetic annihilation photon beams and the method of neutron multiplicity sorting at Lawrence Livermore National Laboratory (USA) and Centre d’Etudes Nucleaires of Saclay (France). The analysis of experimental cross sections employing new objective physical data reliability criteria has shown that many of those are not reliable. The IAEA Coordinated Research Project (CRP) on photonuclear data evaluation was approved. The experimental and previously evaluated cross sections of the partial photoneutron reactions $(\gamma ,1n)$ and $(\gamma ,2n)$ on ${}^{197}\mathrm{Au}$ were analyzed using the new data reliability criteria. The data evaluated using the new experimental-theoretical method noticeably differ from both experimental data and data previously evaluated using nuclear modeling codes gnash, gunf, alice-f, and others. These discrepancies needed to be resolved.

We have investigated under which conditions hyperons (particularly $\mathrm{\Lambda }\mathrm{s}$ and ${\mathrm{\Sigma }}^{-}\mathrm{s}$) can be found in the nuclear pasta phase. As the density and temperature are larger and the electron fraction is smaller, the probability is greater that these particles appear, but always in very small amounts. $\mathrm{\Lambda }$ hyperons only occur in gas and in smaller amounts than would occur if matter were homogeneous, never with abundancies above ${10}^{-5}$. The amount of ${\mathrm{\Sigma }}^{-}$ in the gas is at least two orders of magnitude smaller and can be disregarded in practical calculations.

The total cross section of the ${}^{12}\mathrm{C}+{}^{16}\mathrm{O}$ fusion reaction has been measured at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam, produced by the 5 MV pelletron accelerator at the University of Notre Dame, impinged on a thick, ultrapure graphite target. Protons and $\gamma$ rays were simultaneously measured in the center-of-mass energy range from 3.64 to 5.01 MeV for singles and from 3.73 to 4.84 MeV for coincidence events, using silicon and Ge detectors. Statistical model calculations were employed to interpret the experimental results. The emergence of a new resonance-like broad structure and a decreasing trend in the $S$-factor data towards lower energies (opposite to previous data) are found for the ${}^{12}\mathrm{C}+{}^{16}\mathrm{O}$ fusion reaction. Based on these results the uncertainty range of the reaction rate within the temperature range of late stellar burning environments is discussed.

Photoneutron cross sections were measured in the ${}^{209}\mathrm{Bi}$($\gamma , xn$) reaction with $x=1–4$ at energies from the neutron threshold to 40 MeV using quasimonochromatic laser Compton-scattering $\gamma$-ray beams. A novel technique of direct neutron-multiplicity sorting with a flat-efficiency detector was used. Results are compared with the positron in-flight annihilation data of Livermore and Saclay as well as with bremsstrahlung data. The present neutron yields are consistent with the latest photoactivation measurement with bremsstrahlung. The giant dipole resonance component of the total photoneutron cross section is reasonably reproduced by model calculations of the Hartree-Fock Bogoliubov plus quasiparticle random phase approximation based on the Gogny D1M interaction for both E1 and M1 components. In contrast, the quasideuteron component of the total photoneutron cross section requires a factor of $\sim 3$ enhancement of the Levinger parameter. Furthermore, a survival of large $(\gamma ,n)$ cross sections above 20 MeV may indicate the surface effect on the two-component particle-hole state density. The threshold behavior of photoneutron emission is discussed in terms of the average neutron kinetic energy.

We study the system-size dependence of Knudsen number, a measure of degree of thermalization, for hadron resonance gas that follows the lattice quantum chromodynamics equation of state at zero chemical potential. A comparison between Knudsen numbers for the $\mathrm{AuAu}$ collisions at RHIC and the hadron gas of size similar to the size of high-multiplicity $pp$ events at LHC, reassures the applicability of hydrodynamics in interpreting the features of particle production in high-multiplicity $pp$ events.